The big-honkin' project from hell - it's time!

["Mad Max"]

Alright-alright! Here we go! Yeah buddy - I'm ready to get serious on my next project: 'The Rig', the project from hell.



Let the projects begin! Okay amigos, here's my question of the day: Anyone out there put an Allison 5-speed behind a 6BT and converted to 4x4 with either a 205 or Atlas?



This Summer I'm starting this big honkin project that basically includes merging my 85 crew cab dually and my 93 CTD, while at the same time upgrading the transmission and rear end, and converting to 4x4.



There are several posibilities with the transmission: Go with a 2nd gen core and have it rebuilt via DTT or ATS, etc, or go psudo-industrial and get an Allison or Eaton. Either way I will end up with a lock-up converter so I can upgrade my woah power with an exhaust brake. I like the idea of a nice new Allison but I'm looking for y'all's input. If not that it'll be DTT all the way, but I'm not crazy about throwing all that power through the factory overdrive even if it is pro-built.



Either transmission option will have to be set up for a mated t-case - I'm just gonna do it that way. Anyone ever reworked the input-side of a divorced 205 to work with either a 2nd-gen auto or an Allison?



For the t-case I'm either going with the venerable 205 or an Atlas. If Atlas it'll be the one with the 3. 1 ratio low.



For the rear end I'm planning to go with a brand new D80 dually with discs from Dynatrac. Anything y'all think would be better, or cheaper (eegads they're pricey... )? With this setup, however, there is no provision for a parking brake, and I want one. So, either I fab up some brackets to augment the rear discs (no problem) or I install a driveshaft park brake (not my preferred method). Thoughts?



I already have a D60 dually front end ready to go.



Next, gears. Being in Colorado Springs at 7000' altitude and with the rig weighing in at ~7000lbs, I'm curious about which gears to go with? I like the cruise rpm with my 5500lb truck, empty, with the current 3. 54's, but first gear in my current '93 auto is really too high. I need to either go with 4. 10's and work a healthy overdrive, or (my preferance) is to have the transmission built with a super tall first gear, like a granny. With the Allison I can make use of 4 forward gears plus the overdrive, verses the 3 forward gears in the stocker. Once up to speed the rig just sails, but it needs taller gears, either in the transmission or axles, to get going. Once the transmission is done I'm not going to be worried about power - it'll handle all of what I got, so the 3. 54's, at highway speeds, will be great, and I'd prefer 3. 54's anyway. Thoughts?



So, transmission, rear end, and gear ratio's. I'm planning to make this Rig essentially into an RV, which will incliude mostly long-distance highway driving, usually towing something weighing about 10,000 lbs. I have a nice little '78 Ramcharger for 4x4'ing and camping. The Rig will be 4x4 for snow, bad weather, and occasional mild off roading - nothing too hard-core - it'll be too nice for that, hence the beater Ramcharger.



Any help out there in 1st Gen land?

Many thanks my friends,

- Gonzo

 

[GO 4LO]

Don't get the Atlas. I wouldn't trust it behind a built 6bt. The 205 would probably last just fine, but there are a couple other options that you may not have considered - (1) Rockwell transfer case and (2) Profab or SCS drop box (monster truck style).

I would talk to Jess at highangledriveline.com about a driveline mounted parking brake. He's got a setup that mounts right at the rear output of the transfer case. The nice thing about this setup is your holding power is multiplied by your axle ring and pinion.

What size tires are you planning on running? Once we know that, we can start talking gearing...

Chris

 

[boatpuller]

If it were me and I was going to spend that much$$$$$$ for a new rear axle I'd opt for a 3. 73, a perfect happy medium between the 3. 5s and the 4. 10s.

Also to make it easier I'd go with a newer Dodge/DTT transmission and a 205. They would hold up fine.





Sounds like a fun project, Good Luck,

Caleb

 

[MMiller]

My opinion on gearing is unless you are going with big tires 4. 10's are pretty slow. Sounds like your building an interstate highway tow vehilce. My setup pulls heavy loads down the interstate quite well. Mountians I don't know about, pyro would be the limiting factor I think. I always thought I wanted 3. 73's, but that thought long passed after adding some fuel. I run a 5 spd and want a 6spd. Like said above, tire size will help in gear selection.



As for trans man thats up to you, I would go with a late model/ lock up convertor, transmission builder of your choice trans and prolly be just fine.



Wouldn't it be cheaper to find a dodge dana 80 late model with discs on it already. Dynatrac is real high$$



Sounds like fun, keep us posted.



Michael

 

[dpuckett]

Sam,

If you stay with your 3. 54s and get the transmission and engine upgraded, I see no reason why you wouldnt be able to run just fine with the set up. I used Mom's truck for a summer (when it was still mine) pulling a 24ft box trailer with a STOCK engine and STOCK auto with 3. 54s, sometimes the trailer weighed in at 10K+. Averaged 15mpg @70mph. The Allison is a good transmission- it saves the Duramax from being a total POS. But, I think I'd go for a manual or 4spd auto that has had the DTT/ ATS/ et al treatment, mainly because they came that way and will be easier to get parts and stuff for. You'll end up having to build it all up, no matter which one you go with.



Daniel

 

[Marty1]

Piers just installed a new big Allison in a truck in the past few weeks. I'm told it feels like a bus!

Pastor Bob can fill in the details on it all.

It's a similar project in a truck with HUGE power... 750+?

 

["Mad Max"]

Great advice fellas, very much appreciated, and please don't stop. This kind of thing I only want to do once and have it be exactly what I want.



My tire size will remain the standard dually 235-85/16, and I'll probably use a good A/T. I'd like to run a lighter tire, D-range, but I'm not sure how the weight of the rig and trailer will affect it. With the dual rears the back would probably be fine, but the weight of the CUmmins might tear up the fronts. E's are fine, just heavy and seem to be more difficult to balance.



I already have the adaptor collar b/t the block and transmission in case I go with the DTT 2nd gen route, and I have a line on a decent 4x4 core for about $650. I'd still like to have 4 gears before the o/d hits, with a granny low, and I've pinged the local Allison folks - they didn't seem to be to 'up' on swaps, which is what I figured I'd run into, but they're checking the adaptability for the Cummins/205 setup.

Gonna be a fun project, and I can build it exactly the way I want. Also getting installed will be on-board air and Kelderman air bags at all 4 corners. Plus I can run air tools, connect them into the the trailer and have ready air in the rolling garage any time. I'm not a big fan of knocking 8 dually lugs off of a wheel to change a flat, each at 120 lb/fts, and then knock them back on - enter an impact wrench!

This project will take probably a year, but I'll post pics along the way and I'll keep sort of a tech article going along the process.



Hmmmm.....

..... Pastor Bob - Is there a way to do sort of a personal thread, that won't be seen by the members but would be accessable, like adding another title thread, under the 1st gen column, for project vehicles in work? Thoughts?



Again, thanks for the advice amigos -



- Gonzo

 

[GO 4LO]

Originally posted by SamsRams

My tire size will remain the standard dually 235-85/16, and I'll probably use a good A/T. I'd like to run a lighter tire, D-range, but I'm not sure how the weight of the rig and trailer will affect it. With the dual rears the back would probably be fine, but the weight of the CUmmins might tear up the fronts. E's are fine, just heavy and seem to be more difficult to balance.

Keep in mind that even though the D's may have the weight rating, they will sway more than the E's when trailering.

Chris

 

[MMiller]

My truck came factory with "e"s. At interstate speeds it would get a little squirmy towing heavy. This was with the tires at 80 psi. I always though I needed a rear sway bar. Then I went to the 33's, whick are load range "d". The squirmy is gone, and I run 50psi in the rear when loaded. I have been running the bfgs for 3 sets. I have more problem with the rear chewing up tires then the front. I run about 45psi in the front. I rotate every 5-6000 or when cupping starts on the front. I realize that rotating won't maybe happen on your dually, I sure wouldn't. I don't know if the squirmy was from the tire being narrow, or maybe a little too much air pressure, or what. I would like to go back to a "e" but for now I have had no problems with the "d"s. There is only a couple hundred lbs a tire between the d's and e's that I have run. Run some Michelin XPS Tractions. They are a "e" range and have a steel belt in the sidewall. They are a little $$ but wear like iron. I would be running these but they are not quite big enough, agressive enough for my likes.



C's on the other hand are bad news on our trucks. My brother bought at 94 with brand new tires, but c's, man those tires wore out almost sitting still!! They must have been cheap!





Back to the topic. With stock size I would deffinetly run 3. 55's. IMHO it is a good gear.



Good luck with the allison project. Let us know.

 

[stacerbob]

First: can't remember the name but somebody makes new gearsets that are lower ranges (1st & 2nd) for the automatics. I know I saw it for the 727 & 904 maybe it would fit the 2nd gen OD??

I would go with 3. 73 gears if you are going to tow very much, if just occasionally, I'd stick with the 3. 54 Whats in the front one now??

Why not keep the 205 divorced?? Its great if you have to pull the trans!

Parking brake on the rear of the 205 is awesome! Put it in low and it will hold on the side of a building!!

Keep us informed, it sounds like it will be cool!

 

[dpuckett]

Tires

Mom runs the 215s on her truck; I run the 235s. Both D350s. There is absolutely NO difference in ride quality, but my 235s seem to wear a lot longer than her 215s. They both have an all terrain, leaning hwy tread, but her tires will go 40K at best; mine last a minimum of 50-55K. I cant tell much difference between the two as far as weight to handle; no harder to balance on the LR alone, either.



If you are wanting the air bags to soften the ride, save your money. My father (who happens to live on Ellicott Hwy) has them in his 92 W350, and he had to remove the swaybar to put the front bags on. The thing handles like a kite in a gale; I was afraid to drive it in a crosswind. and to add salt to the wound, it rides like a log wagon with square wheels. I had a 93 W350, almost identical, but with 4. 10s and a flatbed, that rode MUCh better than his did, without the bags.



-DP

 

[John - K5AWO]

SamsRam,



I would stay with the 3. 54 gears. Especially since you are going to stay with the stock 235 tire set. Gonna be short on top end if you go with a higher ratio. You got the 205 to help out with starting up a heavy load already.

 

[GO 4LO]

Originally posted by MMiller

My truck came factory with "e"s. At interstate speeds it would get a little squirmy towing heavy. This was with the tires at 80 psi. I always though I needed a rear sway bar. Then I went to the 33's, whick are load range "d". The squirmy is gone, and I run 50psi in the rear when loaded.

Wow, really? That's exactly the opposite what we've found on two of my friends' trucks. Did you increase tire size when you went to the D? Wider tires tend to squirm less, too... .

Chris

 

[MMiller]

Yeah. I went from stock size e's to the 33's in my profile. They have been "d"s. I have towed many miles with these. Had two sets of them. Now I have some 305 70 R16's I think,need to check, but they are actually larger diameter then the 33's. These actually measure 33" tall, compared to less on the 33X12. 5.



I don't know if I will run these new tires much longer, seem to take a little more power then the 33X12. 5 when pulling trailer. A few more times towing then I will decide.



I cannot verify if the width solved the squirmy problem. I might have had the e's over inflated for the load. I did not have those very long when I started towing. I do considerably more towing now then I did. 10,000 miles on the truck in the last year, about 1,000 without the trailer hooked up.



What did your buddies go to on tires? Brand/Tread.



One thing I have noticed in my part of the country. Alot of the 1970's 2wd "camper special" trucks, fords especially have a wider 12. 5" tire on the rear, then a 8" narrow ones on the front. Maybe they new something way back when?



Michael

 

["Mad Max"]

I've thought about changing the tire size as well, but with the dually applications it is fairly difficult to mess with it, especially widths. I'm pretty happy with the tire diameter and widths of the 235's, and with 4 of 'em in the back the side loads are nearly nil. With as big and heavy a rig as I'm building and with wanting to keep the 3. 54's I agree with y'all that the 235's would be an ideal choice.



This'll be a long-term project (I'm hoping to debut the rig at the '05 Mopar Nationals in Columbus Ohio next August)... or at the '05 Diesel Festival at PDR... which with the Pastor's blessing I'm SURE is going to happen!! I'm really bummed that I won't be able to make the one this year - just too much going on, but '05 should be a very good year.



I'll keep pics of the progress as it goes, and I'll update this thread as I go.



- Sam

 

["Mad Max"]

Allison's not cheap either...

(panting... wiping sweat off forehead... ) - Okay, I do believe that I will be going the tried and true route of a full-tilt DTT 2nd gen transmission. Why? Well, first off everyone that has one loves 'em, and second... well, it appears that the 1000 series that I was looking at won't stand up to the power of my Cummins, particularly the tq, which means that I'd have to go to a 2000 or 3000 series, and unfortunately the series number does NOT denote the price. It appears that the parts for Allisons are made out of unobtainium, like to the tune of $10,000 for the 3000 series. Soooooo, that brings me to plan B:



Can anyone tell me what gear ratios came in the 2nd gen auto's, and has anyone had DTT change gear sets inside the transmission to get a taller 1st and 2nd gear? That is what I'm going to have to do, and that's cool, so now I need to find gears. So, all you transmission guru's out there, I need yer technical expertise.



Oh, the other detractor is that the Allison's are all computer controlled and I'd have to install a TPS, a 'this and that' solenoid, a shifter of some kind, etc etc, and I wouldn't be able to use my neato column mounted o/d button, and THAT may be the biggest reason of all... . !



Hi Ho, Hi Ho, its off to DTT I go... .



Gracias amigos,

- Gonzo

 

[jlast]

why do you want to pitch the d 70 rear for?



upgrade it 35 spline 1. 5" shafts which came stock on other applications in the same lengths needed, and be done with it.



most mid sized rockwell cases are weaker then a 205, monster truck case in a highway cruiser?



use a divorced 205 if you have one, save $$$$ and time if you go wierd on the trans. You have plenty of length for sure.



pretty close to a stock version that wasnt made. no need to spend $4000+ on a axle when you can handle it with what you have.



if you have money to burn, i am holding out my collection cup.

 

[jlast]

BTW gear talking, why not a browney, or under over, etc...

 

["Mad Max"]

well it's not so much that I want to not use the D70 - it works great and is plenty strong, but I'm building a dually so I need to get a different axle anyways... . unless you're saying to convert the 70 to a dually? Considering I'll be doing some 4x4ing while going camping I wanted to go for the beef, hence the D80. Incidentally, there'll be a D70 for sale here sooner or later, plus a 93 auto-o/d, and a bunch of sheetmetal.....

- S

 

[cerberusiam]

I am a little confused by your nomenclature about the gear ratios for 1st gear. Do you want a higher or lower first gear? First seems to be plenty low enough with a 33" or less tire. Much lower and it wouldn't be very usable unless you had a heavy load all the time. I am unaware of a taller 1st gear set but it is probably possible. The 727's used to have a lower 1st gear set that was production in the Highway Patrol cars and if there have not been a lot of changes it should fit the 47RH.



The engine is capable of developing enough torque you should not have problems with the weight and the altitude but that ends being driver preference. If you would be consistently towing around 20k then 4. 10 gears and a taller tire would give better leverage but staying with a tire 33" or under you should not need a lower gear.



The later model OD's have been beefed and tweaked enough they will hold pretty well unless your towing heavy. The biggest problems seem to happen with the rigs towing in the 30k range. The OD drive shell is just not big enough to handle the constant power and it starts eating itself up. All things being equal and judicious driving even that doesn't consistently happen until 80 to 100k.



If your worried about weight and gears I would try a 35" tire with the 4. 10's. That should give enough leverage for heavy loads and allow an efficient rpm range the rest of the times. My personal observations are a dually with 35" tires and some lift is just a "bad ass" looking truck. So much for personal opinions, eh?